CVE-2021-29509
Severity CVSS v4.0:
Pending analysis
Type:
CWE-400
Uncontrolled Resource Consumption ('Resource Exhaustion')
Publication date:
11/05/2021
Last modified:
27/10/2022
Description
Puma is a concurrent HTTP 1.1 server for Ruby/Rack applications. The fix for CVE-2019-16770 was incomplete. The original fix only protected existing connections that had already been accepted from having their requests starved by greedy persistent-connections saturating all threads in the same process. However, new connections may still be starved by greedy persistent-connections saturating all threads in all processes in the cluster. A `puma` server which received more concurrent `keep-alive` connections than the server had threads in its threadpool would service only a subset of connections, denying service to the unserved connections. This problem has been fixed in `puma` 4.3.8 and 5.3.1. Setting `queue_requests false` also fixes the issue. This is not advised when using `puma` without a reverse proxy, such as `nginx` or `apache`, because you will open yourself to slow client attacks (e.g. slowloris). The fix is very small and a git patch is available for those using unsupported versions of Puma.
Impact
Base Score 3.x
7.50
Severity 3.x
HIGH
Base Score 2.0
5.00
Severity 2.0
MEDIUM
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* | 4.3.8 (excluding) | |
| cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* | 5.0.0 (including) | 5.3.1 (excluding) |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
To consult the complete list of CPE names with products and versions, see this page
References to Advisories, Solutions, and Tools
- https://gist.github.com/nateberkopec/4b3ea5676c0d70cbb37c82d54be25837
- https://github.com/puma/puma/security/advisories/GHSA-q28m-8xjw-8vr5
- https://github.com/puma/puma/security/policy
- https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html
- https://rubygems.org/gems/puma
- https://security.gentoo.org/glsa/202208-28